According to the American Gas Association, the total miles of plastic piping in use in natural gas distribution systems in the United States grew from about 9200 miles in 1965 to more than 215,000 miles by 1982, of which, more than 85 percent was formed of polyethylene. While plastic piping, such as polyethylene pipe, is widely accepted as a safe and economical alternative to piping formed from steel for the transportation of gas, such as fuel gas and/or natural gas, a number of pipeline accidents involving plastic pipe have resulted from cracking due to brittle failure.
Therefore, a need exists to form polyethylene pipe resistant to cracking.